برآورد پارامترهای ژنتیکی برخی صفات بادام‌کوهی (.amygdalus scoparia spach) با استفاده از روش reml

تحقیق حاضر با هدف برآورد برخی از پارامترهای ژنتیکی گونۀ بادام کوهی (amygdalus scoparia spach). با استفاده از روش reml انجام شد. بدین منظور از میان پایه های موجود در رویشگاه بادام کوهی در منطقه زرن د در استان کرمان، 20 پایه به صورت تصادفی و با حداقل 100 متر فاصله از هم انتخاب و بذرها به تفکیک پایه جمع آوری شد. بذرها پس از اعمال تیمار سرمادهی با حفظ شجره به نهال تبدیل و به صورت گلدانی در گلخانه آموزشی و پژوهشی دانشگاه یزد کاشته شده، مورد مراقب ت و آبیاری قرار گرفتند . اندازهگیری و ثببت برخی از صفات نهالها در سال اول ،جهت ارزیابی ژنتیکی انجام شد. صفات مورد مطالعه شامل ارتفاع، قطر یقه، تعداد شاخه های فرعی، تعداد برگ، طول پهنک، حداکثر عرض پهنک و شکل برگ بود. نتایج نشان داد که طول و عرض پهنک برگ و پس از آن قطر یقه و ارتفاع نهال بیشترین میزان وراثت پذیری را بین صفات مورد بررسی نشان دادند و بیشترین همبستگی ژنتیکی نیز بین صفات تعداد برگ و قطر یقه، همچنین بین صفات عرض پهنک و ارتفاع نهال و پس از آ ن بین دو صفت قطر یقه و ارتفاع نهال مشاهده شد. در نهایت با توجه به وراثت پذیری های بالای صفات طول و عرض برگ و پس از آن قطر یقه و ارتفاع نها ل در پژوهش حاضر میتوان از این تنوع در سطح مطلوبی جهت بهبود کمی و کیفی اینگونه ارزشمند استفاده نمود.

genetic parameters of some traits of amygdalus scoparia using the reml method

introduction in most breeding programs, genetic diversity is considered a fundamental principle and condition for selection. in other words, understanding genetic diversity and estimating genetic parameters such as heritability, genetic correlation, and variance components of growth traits is a necessary condition for breeding. restricted maximum likelihood (reml) is one of the important methods introduced for analyzing data, and it does not have the limitations of variance analysis for unbalanced and heterogeneous data, such as negative estimates, lack of uniqueness in estimates, lack of appropriate distributional properties, and lack of a useful method for comparing different types of estimates. this method maximizes the non-stationary part of the likelihood function and has the advantage of assigning degrees of freedom to the fixed part of the model, which leads to unbiasedness. it can also be implemented on data that have been affected by selection and deletion; while one of the assumptions of variance analysis is that the data obtained must be random. other applications of this method compared to conventional methods for estimating variance components include directly providing genotypic correlations with greater accuracy. despite the correct and more precise estimation of genetic parameters with these estimators, this method has been used to estimate heritability and genetic correlation in a limited number of domestic studies. in the present study, the estimation of genetic parameters including genetic correlation and heritability of the amygdalus scoparia variety was carried out by evaluating seedlings obtained from seeds of two populations of this variety in kerman province using the reml method, so that ultimately, by identifying the structure, diversity, and existing genetic potential, better decisions can be made for the management and improvement of this valuable variety and the production of more desirable seedlings in the study area. materials and methods initially, seeds were collected from 20 randomly selected stands within the studied habitats. the physiological dormancy of almond seeds, an embryonic dormancy, was overcome by wet chilling. then, the seeds were collected from the mother tree based on a randomized complete block design in three replications and five seedlings in each replication, and were grown to yield seedlings in pots in the research greenhouse of yazd university under greenhouse conditions. at the end of the first growing season, height of seedling, collar diameter, number of leaves, leaf length, maximum leaf width, number of secondary branches and leaf shape (ratio of leaf length to maximum leaf width) were measured and recorded. genetic and environmental variances, genetic correlations and heritability were estimated using the reml method via r software. results and discussion the results of present study showed that the highest genetic variance was assigned to the leaf number, leaf blade length, and seedling height, respectively, and the highest environmental variance was assigned to the leaf number. also, the length and maximum width of the leaf blade, followed by the collar diameter and seedling height, had the highest heritability among all traits studied. heritability analysis revealed the extent to which genetic differences among individuals within a population contribute to variation in a specific trait. this concept examines the extent to which changes in the studied traits depend on their genetics and to what extent they are related to environmental factors and evolutionary history. the extent and speed at which populations are able to adapt also depends on the heritability of quantitative traits. the results also showed that the highest genetic correlation was observed between the leaf number and collar diameter, as well as between maximum width of the blade and seedling height, and then between the collar diameter and seedling height. the main causes of genetic correlation are linkage and gene pleiotropy. some genes increase or decrease both traits at the same time, and others will increase one trait and decrease the other. some genes may exert a strong influence on a specific trait while having minimal effects on others, whereas other genes may show the opposite pattern. in the context of selection-induced changes, it is vital to note how modifying one specific trait may simultaneously have an impact other trait. the more traits are added to the breeding program, the slower the achievement of the intended goals becomes. one advantage of strong correlations between traits is that one trait can be included in the breeding program and the other trait can be improved accordingly. in other words, the correlated response can be exploited to improve different traits simultaneously. conclusion finally, considering the high heritability of leaf length and width traits, followed by collar diameter and seedling height in the present study, this diversity can be used at a desirable level to improve the quantity and quality of this valuable species. also, due to the higher heritability of these traits, if the selection of mother stocks and the production of seedlings for the restoration of forest areas and afforestation in the study area are carried out based on them, we can hope for further improvement and improvement of these areas.